State of the art metallurgy of Ni-based superalloys has established that oxides and carbides represent impurities which are detrimental to many of the mechanical properties of these alloys. Removal of such impurities is desirable and such removal is most readily achieved when the superalloys are in the molten state. Otherwise, the impurities are difficult to dislodge from the superalloys, and the superalloys continue to be contaminated by such impurities.